This invention relates to a harrow of the type comprising an elongate transverse tool bar mounted on ground wheels for transportation across the ground and a plurality of harrow frames suspended from the tool bar and trailing behind the tool bar and including downwardly extending harrow tines for engaging the ground.
The conventional harrow includes the harrow frame having a pair of longitudinally extending rails with transverse tine support bars across the rails and extending outwardly to each side of the rails. The tine support bars carry a plurality of tines each having a coiled upper section wrapped around the tine support bar and a downwardly extending finger section for engaging the ground in a harrowing action.
It is known to modify the harrow action by varying the angle of the tine finger section relative to the axis of the tine support bar so as to vary the inclination of the tine to the vertical in a vertical plane longitudinal of the direction of movement of the tool bar. It is also known to adjust the angle of all of the tines of a frame simultaneously by providing a longitudinally extending actuation bar which carries a plurality of cranks extending from the bar downwardly to the tine support bars so that longitudinal movement of the actuator bar effects rotation of each of the tine support bars about its respective axis.
Various arrangements for supporting the frame from the ground have been provided from simply suspending the frame on chains to various pivot arrangements. In most cases, however the pressure of the harrow frame on the ground is provided solely by the weight of the frame.
In recent years more attention has been given to the action of the harrow on the ground particularly bearing in mind that the harrow may need to operate in increased levels of trash due to low till or no till farming practices.